Interestingly, several of the markers of the protein signature that related to PD‐L1 PEA expression levels have earlier been reported to be associated with ICI pembrolizumab response in melanoma based on their mRNA expression pattern, for example, CCL23, CCL13/MCP‐2, CCL4, CD4, CXCL5, CCL20, and GZMA [23], thus further strengthening the potential for FNA and PEA analytics for capturing BMs of relevance to ICI. Here, CCL23 is linked to melanoma.